This invention relates to a trimming device for a marine propulsion unit and more particularly to an improved connection between the trim unit and the outboard drive.
In a wide variety of outboard drives, both outboard motors and the outboard drive section of an inboard/outboard drive, there is an arrangement incorporated for adjusting the trim position of the pivotally supported outboard drive. In one form of powered trim adjustment, a trim cylinder is carried by the transom of the watercraft and has an actuating rod or thrust member that engages the outboard drive and which urges it about its pivotal axis to change the trim position. In addition, the thrust member of the trim unit takes the driving thrust from the outboard drive during forward propulsion. Normally, the thrust member reciprocates along a fixed axis whereas the outboard drive pivots about a fixed axis. As a result of this, there will be relative movement between the thrust member and the outboard drive that can result in wear, galling and other unsatisfactory conditions. In addition, such relative movement causes noise during operation.
Some of the disadvantageous conditions can be reduced through the position of a roller member (either a ball or a rolling cylindrical member) on the end of the trim thrust member. However, these trim thrust members are normally disposed at an upwardly and rearwardly inclined axis so that water may very well accumulate within them and accumulate under the thrust roller. As a result, corrosion can set in and the advantages will be lost.
One way to avoid corrosion would be to incorporate a grease fitting and grease packing under the roller member. However, this requires servicing. In addition, the grease may be depleted and if not promptly replaced, the same corrosion problems as aforenoted can result.
It is, therefore, a principal object of this invention to provide an improved trim arrangement for an outboard drive.
It is a further object of this invention to provide a trim arrangement for an outboard drive embodying an improved anti-friction arrangement wherein the likelihood of damage through corrosion is substantially reduced.
It is a further object of this invention to provide an arrangement wherein the thrust is transferred between the thrust taking member and the outboard drive through a roller that is carried by the outboard drive.
In connection with tilt and trim units of the type as aforedescribed, one of the principal problems that results from the relative movement is the abrasion, wear and noise as aforenoted.
It is, therefore, a still further object of this invention to provide a thrust transfer arrangement between a trim thrust member and an outboard drive wherein relative movement is reduced.